It’s a common misconception that all teeth are naturally sparkling white.
Many people have teeth that are slightly yellowed. In most circumstances, adult teeth that are very white have been professionally bleached.
If you look hard enough, and you may notice that some of your own teeth are slightly different colours in some places.
They may have yellow, brown, or black marks around the edges.
If this is the case it is likely that your teeth have picked up stains from the food and drink you put in your mouth.
Staining is nothing to worry about it, and can often be fixed by the dentist or hygienist.
In this article we cover the following (click one of the links below to jump to that section)
- Why teeth stain
- How food and drink stain the teeth
- Which food and drinks stain the teeth
- How you can prevent and treat stained teeth
Why do teeth stain?
Kapadia and Jain define tooth staining as “discolouration of a tooth surface or surfaces as a result of ingested materials, bacterial action, tobacco, and/or other substances. “
It seems obvious but there are actually a number of ways of staining our teeth, all caused by what we eat and drink:
- Direct staining – Staining from the colour of the food and drink put in the mouth.
- Indirect staining – Staining from reactions of the food and drink in the mouth with the teeth.
- Internalised staining – Long term damage to the teeth which has caused a colour change to the outside of the tooth.
So whether it is directly or indirectly, food and drink can have a massive impact on staining the teeth.
How do teeth stain?
Normally staining is on top of the surface of the tooth.
Direct and indirect staining, described above, collects on top of the tooth surface, and is staining of the thin removable plaque layer that sits on top of the teeth.
In areas where the plaque is not removed it can and will harden into calculus, which will also stain. Unfortunately, this calculus is nearly impossible for you to remove yourself at home.
Direct staining
The reason that the teeth stain on the outside is because of a thin film that naturally sits on the teeth.
This very thin film is known as the pellicle, and is completely normal. Over the course of a day the pellicle develops into plaque – the soft fuzzy stuff on your teeth. This plaque contains the bacteria responsible for tooth decay and gum disease too.
Food and drink that contain colour pigments will stain this pellicle and plaque layer. This is direct staining is explained in lots of detail by Suchetha et al in their review All About Dental Stains: A Review.
Indirect staining
However, it is also possible for non-coloured food and drink to have a delayed reaction in the pellicle. This chemical reaction may produce colours that stain the plaque, and this is known as indirect staining.
This indirect staining can also happen with some mouthwashes such as Corsodyl, or even for the bacteria in the pellicle to produce staining.
Internalised staining
Extrinsic staining may also develop so that the discolouration of teeth is actually within the outer layer of the tooth (the enamel), instead of on top of the tooth (in the plaque).
This is known as internalised staining.
This deeper staining can form on teeth as a result of dental decay.
When you eat sugary foods, bacteria on the teeth eat the sugars. The bacteria then produce acid as a result and this softens the surface of your teeth. If the teeth remain soft and decay forms it can discolour to a white, brown, or even black patch.
The softened area of decay changes the colour of the teeth which can look like staining. The softened area is also more likely to pick up stains from food and drink.
Sadly this discoloured area can remain on the tooth even if the decay rehardens, and is on a deeper level within the tooth.
Are there any other causes of discolouration?
So we know that teeth can discolour and stain from the outside.
But apart from extrinsic staining, i.e. staining on the outside surface of the tooth, your teeth may also change colour from the inside.
It is common for teeth to yellow or darken with age. They may also change colour if the tooth has died or from medicines you have taken. This change of colour is on the inside of the tooth and is called intrinsic staining.
You can read more about yellow teeth here, but I am going to focus on the food and drink which cause extrinsic staining to teeth.
Can crowns and veneers stain?
Yes! Crowns and veneers can stain.
White crowns and veneers are normally made from very tough materials such as porcelain.
This means that crowns and veneers are very resistant to stains, but it is possible for them to stain if the surface of them becomes damaged.
You might have damaged the surface by using very abrasive whitening toothpastes, or if there are scratches and chips caused by chewing or grinding hard foods or opening things with your teeth. Excessive acid can also damage the surface of crowns and veneers, making them more prone to staining.
You can also get staining at the edges or crowns and veneers, where the crown or veneer meets the tooth.
Can fillings stain?
Yes! Fillings can stain.
White fillings, just like teeth and crowns and veneers, can pick up staining.
The whole filling can darken with time, or may become obvious as the tooth changes colour.
A study by Omata et al in 2006 found that tea, coffee and red wine all significantly changed the colour of the surface of white fillings with time. They found the effect was reduced with brushing. Interestingly, they found red wine to be the worst culprit!
The edges of white fillings are particularly prone to staining, especially if they are not perfectly smooth. These stains can often be removed if you ask your dentist, hygienist, or dental therapist to polish the filling again.
What can make staining worse?
Kapadia and Jain explain that some teeth are more prone to picking up staining from foods and drinks that we eat. Certain things can increase your risk of staining, for example:
- Teeth that have a lot of tooth wear (such as acid erosion or abrasion). The wear reveals the softer part of the tooth which is more to staining. Acid erosion increases staining as it makes teeth more porous.
- Teeth with gingival recession, which reveals the softer dentine inside the root of the tooth. This dentine is more prone to staining.
- Teeth that have certain developmental problems such as enamel hypoplasia. Developmental problems can be passed down in the genes or may even be caused by illness whilst the teeth are growing, and it means the tooth does not grow the same as others. Enamel hypoplasia is a developmental problem which means that the tough outer surface of the tooth, enamel, is damaged and is less tough. Such problems make teeth more porous and so they are more likely to pick up stains.
Foods that stain your teeth
So I have explained that staining can happen on teeth, crowns, veneers, and fillings too.
Basic staining occurs when the plaque layer on the teeth pick up stains from food and drink.
But where does the colour come from?
Many foods and drinks contain natural plant pigments which are broadly classified as polyphenols, and it is these that give food and drink colour. These pigments are split into four different groups and include:
- Chlorophylls, which are a green colour
- Carotenoids, which are yellow-orange-red colour
- Anthocyanins, which are red-blue-purple colour
- Betacyanin, which is a red colour
The much talked about group known as tannins are also polyphenols. The tannin-anthocyanin combination typically colours food red and is common in red wine.
These pigments, as I explained before, become trapped in the plaque on the surface of the teeth and cause staining. This is how foods with lots of darker pigments cause direct staining.
Acidic foods and drinks affect how soft the tooth surface is. A softer tooth surface is more likely to pick up stains from coloured food and drink.
So, whilst food and drink high in acid will not cause staining in itself, consuming them will mean the teeth are more likely to stain from other foods that do have pigments in them.
Food and drink high in acid will also cause erosion revealing dentine which is darker in colour.
Food and drink high in sugar will cause decay which is often dark in colour and which will pick up stains easily. Decay can re-harden but even this can leave a brown or black internalised stain.
Coffee
Coffee can stain your teeth. This is because it contains tannins which can discolour your teeth. As well as these tannins, coffee is also acidic which can cause erosion, and can also speed up the staining process on teeth.
Normally coffee stains will leave brown-black marks at the edge of your teeth.
The roast of your coffee bean, as well as whether or not milk is added, does affect the amount of staining.
Tea
Tea stains your teeth, again because it contains tannins. Regular black tea will normally stain teeth yellow whilst green tea stains teeth grey.
Leardand and Addy found that tea actually stains worse than coffee, and that some brands can have a worse effect than others!
Fizzy drinks (Coke, Lucozade, Red Bull etc.)
Fizzy drinks come in many forms, and include popular sports drinks such as Lucozade and energy drinks such as Red Bull.
Fizzy drinks change the acid level in your mouth. Sadly this means that your teeth are more susceptible to picking up stains.
Studies have been done comparing the amount of staining that different types of drinks have on different filling materials. In a review of these, Lee et al found that the drinks with the lowest pH (i.e. those with the most acid) cause the most staining. This means that very acidic fizzy drinks are likely to do more damage than your tea or coffee.
In addition to this food and drinks can cause erosion, meaning the remove the outside layer of the teeth, the enamel. This exposes the dentine underneath, which is more yellow in appearance. This makes teeth appear darker.
Fizzy drinks often have high levels of sugar which can also cause decay that stains the teeth.
Alcohol
Red wines are well known to cause staining, with many advice columns discussing the issue! This mostly because red wine contains high levels of tannins. Because of this red wine will stain your teeth.
As well as tannins causing red wine to cause stains directly, it is also high in acid. This acid softens the tooth surface, making it more likely that it will pick up stains from other food and drinks too. This theory no doubt also applies to less colourful alcoholic drinks including beer and spirits with fizzy mixers.
Omata et al found during their research in staining white fillings, that red wine causes worse staining compared to tea and coffee.
Curries
Anyone who has spilled curry knows how it can leave a mark! Curries are often rich in foods high in pigments.
Turmeric is often recommended for a variety of health benefits, from skin treatments to tooth whitening! There is anecdotal evidence (read: people’s own experience) that turmeric can reduce tooth staining in a DIY toothpaste.
However, it is unlikely to be the turmeric having the positive effect, and is more likely to be the other ingredients used in these toothpastes.
In fact, turmeric will often stain things it comes into contact with, so it is probably best to avoid if you want to keep your teeth white.
Berries
Dark fruits such as blueberries and blackberries contain high amounts of natural pigments. Although there is little solid research on the effects these have, it is best to avoid these sorts of fruit if you want to avoid picking up stains on your teeth.
Liquorice
A review on the impact of liquorice in the mouth explains that liquorice itself does not cause staining, but has been recognised as having tooth- and tongue-staining ability due to the colour additives.
Licorice can also affect plaque build up, which is the main cause of staining in the mouth.
Fruit Juices
Fruit juices such as orange juice are not normally staining in themselves.
However, as with fizzy drinks, fruit juices are very high in acid and cause erosion. This causes the yellower dentine layer to be more visible on the tooth.
The teeth are also more susceptible to staining from dark foods when they have been exposed to acid.
Sweets / Chocolate
Sugary snacks such as sweets and chocolate do not stain your teeth. But they can cause decay, and this decay can cause your teeth to appear black.
Sauces
Dark coloured sauces, or those containing brightly coloured ingredients, for example tomato sauce or soy sauce, may cause staining in some cases, especially if eaten very often, however there is very little evidence to explain how or why.
How to prevent stains
There are some simple steps you can take to reduce the amount of staining that builds up on your teeth, including:
- Keeping your mouth clean
- Reducing the amount of time staining food and drinks are in contact with your teeth
- Weakening the staining ability of your food and drink
- Avoiding staining food and drinks by swapping them for something less harmful
- Chewing sugar free chewing gum
Keep your mouth and teeth clean
Brush twice daily with an electric toothbrush, and clean in between your teeth every day with floss or interdental cleaners. This will reduce the plaque and calculus build up on your teeth. This will mean there is less plaque to pick up staining! Clean your tongue with a tongue scraper if your tongue picks up stains easily.
Reduce the amount of time staining food and drinks are in contact with your teeth.
This doesn’t necessarily mean cutting them out altogether. But you can reduce harm by drinking liquids through a straw, or rinsing with water after having a staining food or drink. But avoid brushing too soon after acidic food and drink as this can cause erosion.
Weaken the staining food and drink.
For example, add milk to tea and coffee, or switch to a less staining type of tea.
Make food swaps.
Swap staining tea and coffee for hot water infused with lemon (just beware of the acid content), or swap staining fruits for raw crunchy vegetables.
Chew sugar free chewing gum.
This will help clear food and drink from your mouth quicker, and increase the amount of protective saliva you produce.
For crowns and veneers you can avoid staining by looking after them! Brush twice daily with a minimally abrasive toothpaste. Avoid damaging the surfaces by not using your teeth to open things, and avoiding a diet that is too high in acid.
How to remove stains
Removing stains in the early stages can be done with good home care, including brushing twice daily with an electric toothbrush, and thoroughly cleaning between the teeth. This will remove the plaque that picks up stains.
Whitening toothpastes are generally more abrasive than regular toothpastes, and can genuinely help with removing stains. They will not, however, whiten the whole tooth, as Jon explains in the video below:
Stains that are more stubborn can be removed professionally with a scale and polish, or with a more modern AirFlow treatment. Try not to go too often as polishing can be abrasive and lead to tooth wear and sensitivity.
More stubborn staining may require treatment with professional tooth whitening.
Generally food and drink stains are fairly superficial and can be removed with these simple treatments. In extreme circumstances the staining may not be able to be fully removed and you may consider covering them up, for example with fillings or veneers.
Should you brush your teeth after eating to prevent stains?
If staining is a build up of pigments on the plaque, it would make sense that brushing your teeth straight after eating or drinking will reduce staining.
Brushing will remove the pigments responsible for causing tooth staining. Brushing will also remove the plaque that is stained by these pigments.
Sadly, there is little evidence to support the benefit of this, so I’m not sure how much difference this will make in the real world.
We do know that brushing too soon after eating or drinking acid can cause damage such as enamel erosion, so should be avoided, as explained in this article about brushing before or after breakfast.
All things considered, as a dentist, I wouldn’t recommend brushing straight after eating. The better option would be to rinse with water or mouthwash and make sure you are brushing twice a day for two minutes to prevent plaque build up.
FAQ
Does coffee stain teeth?
Yes, coffee stains your teeth.
Does tea stain teeth?
Yes, tea stains your teeth.
Does green tea stain teeth?
Yes, usually more of a grey than yellow colour.
Why does decay cause teeth to stain?
Decay softens the tooth making it more prone to staining from food and drink. Decay is also dark in colour so can make teeth appear stained. Even if decay rehardens, the stains can be permanent, also known as internalised staining.
Why do acids cause food to stain?
Acidic food and drink softens the tooth surface. The porous enamel is more likely to pick up stains from food and drink.
Can tooth staining be removed?
Most tooth staining can be removed either with good cleaning at home, or with professional cleaning by a dentist or hygienist. Only tough internalised stains may need to be covered up with fillings.
How can I prevent tooth staining?
You can prevent tooth staining by avoiding acidic and staining foods, or keeping them to only once a day. Keeping your teeth clean and chewing gum can also prevent tooth staining.
